Research! Look up each antibiotic from our lab and describe what it does to bacteria. As a group,...

Research!

• Look up each antibiotic from our lab and describe what it does to bacteria.

• As a group, draw a picture that you think best represents how each antibiotic works.

Cells!

– The cell is the lowest level of structure that can perform all activities required for life.

• Cell Theory:– All living organisms are composed of cells.– All cells come from other cells.

We can distinguish two major types of cells:ProkaryoticEukaryotic

Photo source: Wikipedia

The prokaryotic cell is simple, small, and contains no organelles.

The eukaryotic cell is larger and more complex and contains organelles.

Prokaryotic and Eukaryotic Cells:

(DNA)

(DNA)

Cytosol

Cytosol

A prokaryotic cell

Two typical kindsof eukaryotic cells:- Animal cells- Plant cells

Prokaryotic and Eukaryotic Cells: What do all cells have in common?

(DNA)

(DNA)

Cytosol

Cytosol

Plasma membraneCytosolRibosomesChromosomesmade of DNA A prokaryotic cell

Prokaryotic and Eukaryotic Cells: What is their most significant difference?

Eukaryotic cells havemembrane-bound organellesthat performspecialized functions

Prokaryotic cellsdo not

Look more closely at cellular structures and their functions

• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System

– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles

• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella

Plasma Membrane– The plasma membrane separates the living

cell from its nonliving surroundings.

- Regulates trafficinto and out of the cell

- Allows cell to interact with environment

Membrane Function– A closer look at our membranes

Hydrophobic region

Hydrophilicregion

Cell Surfaces

– Most cells secrete materials for coats of one kind or another that are external to (outside of) the plasma membrane.

– Animal cells have an extracellular matrix and cell junctions,

• Which helps hold cells together in tissues and protects and supports them (not shown).

Cell Surfaces

Try giving your skin a good pull. If your skin is made out of cells,how do they all stick together? Extracellular matrix and junctions!

– Plant cells and bacterial cells have cell walls,• Which help protect the cells, maintain their shape, and keep

the cells from absorbing too much water.

Cell Surfaces

Plant Cell Walls: Cellulose

Bacterial Cell Walls: Peptidoglycan

Osmosis and the Cell Wall

Solute in = solute outWater travels equally

Solute in > solute out Water travels in

Solute in < solute out Water travels out

Structure Meets Function in a Cell

• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System

– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles

• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella

The Nucleus:Genetic Control of the Cell

– The nucleus is the manager of the cell.• Genes on the DNA in the nucleus store information

necessary to produce proteins.

Prokaryotes do not have nuclei. Their genes (on DNA) are in the nucleoid region

Structure and Function of the Nucleus– The nucleus is bordered by a double membrane

called the nuclear envelope.• It contains chromatin and a nucleolus.

Chromatin: long strands of DNA and associated proteins. The DNA stores the genetic information (genes).

Nucleolus: assembles ribosomes

Ribosomes: Protein Synthesis– Ribosomes are responsible for protein synthesis.

How DNA Controls the Cell– DNA controls the cell by transferring its coded

information into RNA.• The information in the RNA is used to make proteins.

Eukaryotic cell

Prokaryotic cell

Structure Meets Function in a Cell

• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System

– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles

• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella

The Endomembrane System: Manufacturing, Distributing, and Storing Cellular Products

Not found in bacterial cells!

Structure Meets Function in a Cell

• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System

– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles

• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella

Energy Conversion:Chloroplasts & Mitochondria

– Cells require a constant energy supply to do all the work of life.

Not found in bacterial cells!

Chloroplasts– Chloroplasts are the sites of

photosynthesis, the conversion of light energy to chemical energy.

All little green circles are chloroplasts

Cell walls

Mitochondria– Mitochondria are the sites of cellular

respiration, which involves the production of ATP from food molecules.

Structure Meets Function in a Cell

• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System

– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles

• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella

The Cytoskeleton:Cell Shape and Movement

– The cytoskeleton consists of a network of fibers.

Also, recently found in bacterial cells!

Cytoskeleton– Mechanical support to

maintain cell shape

– Can change cell shape to allow movement

Structure Meets Function in a Cell

• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System

– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles

• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella

Cilia and Flagella– Cilia and flagella are motile appendages.

Not found on most plant cells!

– Flagella propel the cell in a whiplike motion.

– Cilia move in a coordinated back-and-forth motion.